Fibers having low and high coefficients of friction surfaces

ABSTRACT

The present invention relates to fibers having both relatively low and relatively high coefficient of friction characteristics. The fibers of the present invention are useful for toothbrush bristles and dental floss.

RELATED APPLICATIONS

[0001] This is a continuation-in-part of application Ser. No.09/661,235, filed on Sep. 13, 2000, which, in turn, is a divisional ofapplication Ser. No. 09/021,325, filed on Feb. 10, 1998, both of whichare incorporated herein by reference.

FIELD OF THE INVENTION

[0002] This invention relates to fibers having both a relatively lowcoefficient of friction surface and a relatively high coefficient offriction surface and methods for producing such fibers. The fibers maybe used as dental floss and may be incorporated into articles such astooth brushes, floss picks and apparel.

BACKGROUND OF THE INVENTION

[0003] A major health concern involves gum disease and the resultingdecay or loss of teeth. Gum disease, normally referred to as gingivitis,is caused by bacterial action from the formation of plaque about theteeth and/or the entrapment of food particles in the spaces between andunder the teeth. Removal of plaque and entrapped food particles reducesthe risk of gingivitis, and improves oral hygiene as well. Brushing andflossing are the two ways that plaque and entrapped food can be removedfrom the teeth and gums.

[0004] Tooth brushes and dental floss are made from fibers. Fibers aretypically structures whose length is significantly greater than any oftheir other dimensions, usually their length is at least 100 times aslarge as their diameter. Fibers may be natural, synthetic, organic orinorganic. Often, the bulk polymers from which synthetic fibers areformed, may be useful as plastics or films depending upon the type anddegree of molecular orientation, and the relative dimensions of thefinished structure.

[0005] Dental floss is conventionally made from sinuous strands offilaments that are bulked together. The filaments are generally of thesame type and can contain additives, such as flavorings, or compoundsthat make it easier for the floss to be inserted between the teeth.

[0006] Dental floss is available in either a waxed or unwaxed variety.Waxed dental floss is generally comprised of multifilament yarns coatedwith a white or colorless wax usually having a melting point of fromabout 140 to 200° F. It is believed by some that flossing with a waxedfloss may leave residues of wax on the teeth which may be harmful,whereas others merely do not like the waxy sensation in their mouths.Unwaxed dental floss is generally composed of multifilament yams twistedtogether and coated with a non-wax bonding material. While satisfactoryfor many users, such floss presents problems for some who find itdifficult to insert the floss in tight spaces between the teeth. This isdue in part to the inability of the various filaments to easily slideover one another as the floss is forced between contacting teeth as wellas in part due to the absence of wax. The sliding of the filaments overthe tooth surface and over one another is inhibited by the nature of thematerials from which commercially available floss products are made.These include a plurality of individual filaments made from substancessuch as nylon 6, nylon-6, 6-rayon, polyester, acetate polymers,polypropylene and similar plied multifilament yams, as well as cotton,wool and other staple yams.

[0007] With respect to the fibers claimed and disclosed in the presentinvention, reference is made to U.S. Pat. No. 5,904,152. This patentrelates to dental flosses, including multicomponent coextruded filamentsand/or filaments having a multilobal cross-section. The flosses arecapable of bulking.

[0008] Further, U.S. Pat. No. 5,518,012 relates to expanded PTFE dentalfloss. The floss contains a fiber of increased thickness so that thefloss is maintained in an unfolded orientation.

[0009] U.S. Pat. No. 5,209,251 relates to dental floss produced fromexpanded PTFE and coated with a microcrystalline wax to increase thefriction coefficient of the floss.

[0010] U.S. Pat. No. 5,033,488 relates to porous, expanded PTFE coatedwith microcrystalline wax. The floss may also contain one or moreactives and/or dentally acceptable agents.

[0011] The flosses discussed in these references contain a base fibercoated with a wax for ease of insertion between the teeth and gums. Suchlow frictional wax flosses, however, do not incorporate a relativelyhigher coefficient of friction portion that imparts to the floss anabrasive characteristic for, for example, dislodging and removing foodparticles.

[0012] Fibers are usually produced by drawing, spinning or stretching abulk material so that the molecules are predominantly aligned in thedrawn, spun, or stretched direction. Subsequent drawing of the fiberbelow its melt temperature significantly alters the fiber's mechanicalproperties.

[0013] Fibers may also be produced by slitting an oriented film orsheet. If prepared from oriented sheet, the slit sheet will requiresubsequent drawing to obtain the required fiber properties.

[0014] Most synthetic fibers may be produced as long continuous filamentor as staple. Staple is produced by cutting continuous filament intoshort lengths. Most natural fibers are produced as staple, with silkbeing a notable exception.

[0015] Continuous filament and staple are often post treated to altertheir surface characteristics. Such surface treatments may includescouring by surface active agents to remove surface impurities, sizingby a surface coating to protect the fiber during weaving, dyeing tomodify the color of the fiber and lubricating by refined petroleumproducts to reduce static and the coefficient of friction.

[0016] It is apparent in the prior art that coating a staple or filamentwill usually provide a fiber having a surface completely covered by thecoating. In cases where a low coefficient of friction is desired, thismay sometimes be undesirable. For applications in which a lowcoefficient of friction might be needed on the top and/or bottom surfaceof a fiber, uniformly low friction fibers and uniformly coated fibersmight not provide the optimum balance of properties for application indental floss and tooth brushes.

[0017] Furthermore, uniformly low friction fibers or uniformly coatedfibers may not provide desired properties for use in apparel. Mostapparel is made out of many materials, natural and man-made. Theyinclude cotton, wool, silk, linen, leather, vinyl, nylon—polyamides andpolyamide co-polymers, LYCRA SPANDEX in different filamentconfigurations, orlon polyvinylidene fluoride, such as KYNAR andpolyester, for example, polyethylene terepthalate, glycol modifiedpolyesters, such as PETG, KODURA, rayon, orlon cellulosic fiber blends,and the like, as well as blends of the above.

[0018] Of course, apparel, either directly or indirectly, contacts thebody surface of the wearer. The movement of the wearer causes frictionalcontact between the wearer's body surface and the apparel. Thisfrictional contact can cause irritation, blisters, and callouses and isparticularly a problem in sporting apparel wherein the formation ofirritations, blisters, and callouses is exacerbated by the rapid and/orrepetitious body movements related to the particular activity.Additionally, it is noted that most apparel has specific areas of highbody surface/apparel contact which produces a majority of theirritations, blisters, and callouses.

[0019] One way to overcome the problems caused by frictional contactbetween an article of clothing and the wearer is to make the clothingfrom low friction fabric. Such fabric may be made from fibers that havea low friction outer surface. However, when the low friction fibers arewoven together to produce a fabric the low fiber-to-fiber coefficient offriction is likely to decrease fabric stability by enabling the fibersto easily slide among themselves. This problem is recognized in U.S.Pat. No. 5,035,111 to Hogenboom et al. Hogenboom attempts to overcomethe problem by spinning yams or fibers having a low coefficient offriction with yarns or fibers having a high coefficient of friction.However, Hogenboom does not disclose modifying the fibers themselves.Moreover, Hogenboom's fibers are not made through coextrusion,lamination, and/or coating of a film, sheet or fiber, whereby only aportion of the fiber surface exhibits a low coefficient of friction.

OBJECTS AND SUMMARY OF THE INVENTION

[0020] It is an object of the present invention to provide a fiberhaving both relatively low and relatively high coefficient of frictionareas.

[0021] It is a further object of the present invention to provide adental floss with a relatively low coefficient of friction area and arelatively high coefficient of friction area that imparts the dentalfloss with the ability to easily get between teeth yet effectively cleanaway plaque and tartar.

[0022] It is still another object of the present invention to provide afiber comprising a relatively low coefficient of friction portion and arelatively high coefficient of friction portion, wherein the relativelylow coefficient of friction portion is adjacent to the relatively highcoefficient of friction portion.

[0023] It is another object of the present invention to provide a fibercomprising a relatively low coefficient of friction portion and arelatively high coefficient of friction portion, such that when thefiber is viewed in cross-section, the relatively low coefficient offriction portion makes up about 50% of the total cross-sectional areaand the relatively low coefficient of friction portion is adjacent tothe relatively high coefficient of friction portion.

[0024] It is another object of the present invention to provide a dentalfloss comprising a continuous relatively high coefficient of frictionportion spaced between two continuous relatively low coefficient offriction portions, such that each continuous portion traces a path alongthe length of the fiber.

[0025] It is another object of the present invention to provide a dentalpick comprising a continuous relatively high coefficient of frictionportion spaced between two continuous relatively low coefficient offriction portions, such that each continuous portion traces a path alongthe length of the pick.

[0026] It is yet another object of the present invention to provide adental floss comprising a plurality of filaments, wherein each filamentcomprises a relatively low coefficient of friction portion and arelatively high coefficient of friction portion.

[0027] It is still another object of the present invention to provide adental floss comprising a plurality of filaments, wherein each filamentcomprises a relatively low coefficient of friction portion and arelatively high coefficient of friction portion, and wherein the totallow coefficient of friction portion of the plurality of filaments makesup about 50% of the cross sectional area of the floss.

[0028] It is yet another object of the present invention to provide adental floss comprising first and second filaments, wherein the firstfilament has a relatively high coefficient of friction and the secondfilament has a relatively low coefficient of friction, wherein the firstand second filaments are each 50% of the total volume of the dentalfloss, and wherein the first and second filaments are substantiallyevenly dispersed throughout the dental floss.

[0029] Yet another object of the present invention is to provide adental floss comprising an inner core surrounded by an outer core,wherein the inner core comprises filaments having a relatively highcoefficient of friction, and wherein the outer core comprises filamentshaving a relatively low coefficient of friction.

[0030] It is still another object of the present invention to provide amethod of producing fibers having low coefficient of friction surfacesor smooth surfaces for incorporating into fabrics while retaining theproperties desirable for weaving the fiber into a fabric.

[0031] Specifically, it is an object of the present invention to providea fiber having low coefficient of friction surfaces that retains thefabric stability after being woven into a fabric.

[0032] More specifically, it is an object of the present invention toproduce through coextrusion, lamination, and/or coating a fiber havingat least one low coefficient of friction surface and one relatively highcoefficient of friction surface.

[0033] It is still another object of the present invention to provide adurable high tensile-strength fiber having at least one low coefficientof friction surface and being suitable for use in weaving a fabrichaving at least one low coefficient of friction surface.

[0034] An aspect of this invention is to provide fibers prepared fromoriented film or sheet. The film/sheet is formed through coextrusion,lamination, and/or coating such that the top and/or bottom surfaces havea different coefficient of friction than the center or internal layer(s)of material. Such fibers may be twisted in preferred sequences and/ororientations such that the center layer(s), having a higher coefficientof friction, interact with other members of the fabric construction toprovide increased woven fabric construction stability. This stability isrealized by having the higher coefficient of friction surfaces of thecoextruded, laminated, and/or coated fiber contact additional surfacesof the gross fabric structure.

[0035] Another aspect of this invention is to partially coat a “basefiber” with a low coefficient of friction material such that the coatedsurface of the base fiber has a lower coefficient of friction than thenon-coated surface. Like the fibers prepared from film or sheet, thepartially coated fibers may be twisted in preferred sequences and/ororientations such that the non-coated surfaces, having a highercoefficient of friction than the coated surfaces, interact with othermembers of the fabric construction to provide increased woven fabricconstruction stability.

[0036] Still another aspect of this invention is to provide coextruded,laminated, and/or coated fibers in which the core layer/base fiber hasshock absorbing characteristics (e.g., core layer(s) are open or closedcelled foams). Such fibers provide increased cushioning values inaddition to a low coefficient of friction on their treated surfaces.

[0037] Yet another aspect of this invention is to provide fibers inwhich the core layer/base fiber provides desirable thermalcharacteristics. For example, the core layer/base fiber may include aninsulating material for restricting the escape of heat energy, or aradiant material for facilitating the escape of heat energy.

[0038] It is apparent that the fibers of the present invention may beused to create fabrics having enhanced woven fabric stability, shockabsorption capacity and/or thermal properties. Thus the presentinvention provides for a decrease in intra- and extra-fabric coefficientof friction, while at the same time increasing fabric stability andenhancing thermal characteristics.

[0039] By using low coefficient of friction materials during either thecoextrusion, lamination, and/or coating processes, a novel fiber isproduced, with at least a portion of the surface of the novel fiberexhibiting low coefficient of friction characteristics and the remainingsurface portion of the fiber exhibiting relatively higher coefficient offriction characteristics.

[0040] The novel fiber can be incorporated into a fabric to produce afabric having a smooth surface, and the smooth surface fabric can, inturn, be incorporated into clothing to produce clothing having a smoothsurface.

[0041] Other objects, features and advantages according to the presentinvention will become apparent from the following detailed descriptionof the illustrated embodiments when read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042]FIG. 1 is a cross sectional view of a fiber having low coefficientof friction surfaces according to the present invention; wherein thecoefficient of friction of the top surface is the same as thecoefficient of friction of the bottom surface, and both the top andbottom surfaces have a coefficient of friction that is lower than thecoefficient of friction of the center layer/side surface.

[0043]FIG. 2 is a cross sectional view of a fiber having low coefficientof friction surfaces according to the present invention; wherein thecoefficient of friction of the top surface is different from thecoefficient of friction of the bottom surface, and either one of, orboth of, the top and bottom surfaces has a coefficient of friction thatis lower than the coefficient of friction of the center layer/sidesurfaces.

[0044]FIG. 3 is a cross sectional view of a fiber having low coefficientof friction surfaces and an expanded center layer according to thepresent invention; wherein the coefficient of friction of the topsurface is different from the coefficient of friction of the bottomsurface, and either one of, or both of, the top and bottom surfaces hasa coefficient of friction that is lower than the coefficient of frictionof the center layer/side surfaces.

[0045]FIG. 4 is an isometric view of a base fiber that is partiallycoated with a low coefficient of friction material according to thepresent invention.

[0046]FIG. 5 is a cross sectional view of a tooth brush bristle havingrelatively low and relatively high coefficient of friction surfacesaccording to the present invention.

[0047]FIG. 6 is a monofilament dental floss having relatively low andrelatively high coefficient of friction surfaces according to thepresent invention.

[0048]FIG. 7 is a multifilament dental floss having a plurality offilaments wherein each of the filaments have both relatively low andrelatively high coefficient of friction surfaces according to thepresent invention.

[0049]FIG. 8 is a multifilament dental floss having a plurality offilaments wherein about 50% of the filaments have a relatively lowcoefficient of friction and about 50% of the filaments have a relativelyhigh coefficient of friction according to the present invention.

[0050]FIG. 9 is a multifilament dental floss having an inner core ofpredominantly relatively high coefficient of friction filamentssurrounded by an outer layer of predominantly relatively low coefficientof friction filaments according to the present invention.

[0051]FIG. 10 is a floss pick having both a low coefficient of frictionportion and a relatively high coefficient of friction portion accordingto the present invention.

DETAILED DESCRIPTION

[0052] The fibers of the present invention may be used to provideimproved dental flosses and toothbrush bristles. One of the advantagesof such improved flosses and bristles is that they are more effective atcleaning plaque from the teeth. Other advantages include ease ofgripping, ease of insertion between the teeth, and low cost.

[0053] The fibers of the present invention may be comprised of mono- ormulti-filaments. In one embodiment, reference is made to FIG. 6 whereina monofilament dental floss is presented having relatively low andrelatively high coefficient of friction surfaces according to thepresent invention.

[0054] In another embodiment, reference is made to FIG. 7 wherein amultifilament dental floss is presented having a plurality of filamentswherein each of the filaments have both relatively low and relativelyhigh coefficient of friction surfaces according to the presentinvention.

[0055] In a further embodiment, reference is made to FIG. 8 wherein amultifilament dental floss is presented having a plurality of filamentswherein about 50% of the filaments have a relatively low coefficient offriction and about 50% of the filaments have a relatively highcoefficient of friction according to the present invention.

[0056] In a still further embodiment, reference is made to FIG. 9wherein a core of relatively high coefficient of friction fibers aresurrounded by fibers having a relatively low coefficient of friction.The low friction fibers assist in the ease of insertion of the flossbetween the teeth. During the insertion process, the low friction fiberspartially separate exposing the relatively high coefficient of frictionfibers to the gums. The high friction fibers come into contact with the,for example, food particles between the teeth and gums and remove theparticles and massage the gums.

[0057] The fiber of the present invention is produced by known methodsin the art. The fiber of the present invention is preferably produced byslitting oriented film or sheet, and more preferably produced byorienting and slitting extruded film or sheet, the extruded film orsheet being formed via a coextrusion process. Alternatively, a single ormulti-layer film or sheet may be laminated to other materials such thatits top and/or bottom surfaces are different from the core layer(s). Asan additional alternative, a single or multi-layer film may be coatedwith one or more materials such that its top and/or bottom surfaces aredifferent from the core layer(s). As still another alternative, a “basefiber” may be partially coated with a low coefficient of frictionmaterial such that the coated surface of the base fiber has a lowercoefficient of friction than the non-coated surface. A still furthermethod includes extrusion. Some fibers suitable for use in the currentinvention are discussed in U.S. patent application Ser. No. 09/021,325,which is incorporated herein by reference.

[0058] Another method includes sheath and core. In the sheath and coremethod, exemplified in FIG. 9, the floss comprises an outer sheath whichis soft, slippery, or abrasive, to improve the ease of insertion,comfort and cleaning capability, respectively, of the floss, and aninner core that provides other desired physical properties, such asstrength and resiliency and/or serves as a carrier for additives, suchas flavors, scents and medicaments. Thus, the sheath may comprise one ormore relatively low coefficient of friction components, whereas the coremay comprise one or more relatively high coefficient of frictioncomponents.

[0059] In the film/sheet embodiment, low coefficient of frictionmaterials are used to form the top and/or bottom surfaces of the film orsheet, such that the top and/or bottom fiber surfaces exhibit lowcoefficient of friction characteristics. Accordingly, the fibers thatresult from slitting the film/sheet having top and/or bottom surfacesthat exhibit low coefficient of friction characteristics, and sidesurfaces that exhibit relatively higher coefficient of frictioncharacteristics.

[0060] The relatively high coefficient of friction portion is comprisedof polyester, nylon, acrylics, aramids, polyethylene, polyurethane andplastic copolymers. Suppliers include, for example, DuPont, Nylestar,Wellman and Foss. One of ordinary skill in the art would understand inlight of the present disclosure that more than one relatively highfriction polymeric component may be used, such as, for example, a blendof two, three or four different polymeric components may be used.

[0061] The materials that may be used to form relatively low coefficientof friction portion include, but are not limited to,polytetrafluoroethylene (PTFE), boron, HALAR™, molybdenum sulfide,ultrahigh molecular weight silicone, siloxane, silicone/silane modifiedpolymers, graphite, fluorinated high molecular weight polyolefins orcyclic organic compounds, non-modified polyolefins, or other fluorinatedpolymers. Suppliers of such low low-friction materials include, forexample, DuPont, Dow Corning, Ausimont and General Electric.

[0062] The low coefficient of friction materials must exhibit surfaceproperties that reduce the coefficient of friction. Preferably, the lowcoefficient of friction material is selected from the group consistingof silicone, silicone copolymers, silicone elastomers,polytetrafluoroethylene, homopolymers and copolymers thereof, graphite,boron, polypropylene and polyethylene.

[0063] The most preferred low coefficient of friction material addedduring coextrusion/lamination/coating and later incorporated into dentalfloss, tooth brushes, or a fabric that comprises an article of clothingis a polytetrafluoroethylene (“PTFE”), also known by its trademarkTeflon™. PTFE is a linear polymer with each polymer chain having a lowcoefficient of friction. PTFE is a fluorocarbon polymer, which isdefined in the Condensed Chemical Dictionary, 8th Edition, as includingpolytetrafluoroethylene, polymers of chlorotrifluoroethylene,fluorinated ethylenepropylene polymers, polyvinylidene fluoride,hexafluoropropylene, etc. Also preferred for the present invention arepolymers and copolymers based on chlorotrifluoroethylene, poly (vinylfluoride) and poly (vinylidene fluoride). Copolymers of ethylene and/oradditional low coefficient of friction silicone polymers are alsoacceptable.

[0064] Moreover, the fibers of the invention may also compriseadditives. Such additives include, for example, anti-microbials, bakingsoda, peroxide abrasives, flavorings and pigments. The advantages ofsuch additives include, for example, whitening of the teeth, ease ofhandling and pleasing taste.

[0065] The “exposed surfaces” of a fiber according to the presentinvention are formed as a result of slitting the oriented film/sheet, oras a result of only partially coating the base fiber. As mentionedabove, these exposed surfaces can have a higher coefficient of frictionthan the “unexposed surfaces”, due to the exposure of the corematerial/base fiber. More specifically, the exposed surfaces havecoefficients of friction ranging from 1.10 to 5.00 or more times thecoefficient of friction of the unexposed surfaces. The exposed surfacecoefficient of friction depends upon the exposed area, the chemicalmake-up of the exposed area and the surface characteristics of theexposed area. Advantageously, the fibers of the invention are less proneto detract from the stability and durability of fabric then are coatedfilament or stable, because unlike coated filament and stable, thefibers of the invention have exposed surfaces of a relatively highcoefficient of friction.

[0066] In the film/sheet embodiment, typical exposed surfaces consist of“tie-layers” such as adhesives (e.g., Admer™ and Bynel™) adjoining theprimary strength layers. Fillers, such as mica, calcium carbonate, talcor other particulates may be added to any of the layers to affectadhesion, barrier and/or ergonomic factors. Combinations of fillers andfoaming agents may also be used as the core layers. The core layers mayalso consist of engineering resins (e.g., Nylon, Polyester) or naturalfibers, modified to improve the performance of such layers.

[0067] Moreover, the core layers/base fiber may be selected to impartthe fiber of the invention with desirable characteristics. In oneembodiment, the core layer/base fiber has shock absorbingcharacteristics (e.g., core layer(s) are open or closed celled foams) toprovide increased cushioning values in addition to a low coefficient offriction on the treated surface. In another embodiment, the corelayer/base fiber provides desirable thermal characteristics in additionto a low coefficient of friction on the treated surface. For example,the core layer/base fiber may include an insulating material forrestricting the escape of heat energy, or a radiant material forfacilitating the escape of heat energy.

[0068] Additionally in the film/sheet process, by using materials havingdifferent coefficients of friction for respective sides of thefilm/sheet the resulting coefficient of friction of the fiber can becontrolled so that the coefficients of friction of the top and bottomsurfaces of the fiber differ. In turn, such fibers may be used to form afabric wherein the coefficient of friction of the top and bottom surfaceof the fabric differ. For example, any of the previously mentioned lowfriction materials can be used to create the low friction surface of thefabric, while a high friction material such as rubber, cotton,elastomers, polyacrylates, polymethacrylates, and polyurethanes can beused to create the relatively high friction surface of the fabric. Moregenerally, the relatively high friction materials may include anymaterials having a coefficient of friction greater than 0.3. In onepossible embodiment a bathing suit can be designed to have a lowcoefficient of friction on the suit surface exposed to water, toincrease swimming speed, and a high coefficient of friction on thesurface exposed to the wearer, to minimize suit movement on the body.Such a bathing suit could readily be produced using fabrics made up offibers obtained from the previously described films/sheets.

[0069] Exemplary embodiments of the invention are illustrated in FIGS. 1to 10 in which FIGS. 1-4 are discussed in Ser. No. 09/661,285. FIG. 5 isone embodiment of the present invention and depicts a cross sectionalview of a tooth brush bristle having relatively low and relatively highcoefficient of friction surfaces. FIG. 6 is another embodiment of thepresent invention and depicts a monofilament dental floss iscontemplated having relatively low and relatively high coefficient offriction surfaces. FIG. 7 is yet another embodiment of the presentinvention and depicts a multifilament dental floss having a plurality offilaments wherein each of the filaments have both relatively low andrelatively high coefficient of friction surfaces. FIG. 8 is stillanother embodiment of the present invention and depicts a multifilamentdental floss having a plurality of filaments wherein about 50% of thefilaments have a relatively low coefficient of friction and about 50% ofthe filaments have a relatively high coefficient of friction. FIG. 9 isa further embodiment of the present invention and depicts amultifilament dental floss having an inner core of predominantlyrelatively high coefficient of friction filaments surrounded by an outerlayer of predominantly relatively low coefficient of friction filaments.FIG. 10 is a still further embodiment of the present invention anddepicts a floss pick having both a low coefficient of friction portionand a relatively high coefficient of friction portion.

[0070] One embodiment according to the present invention is amultilayered fiber with one surface having a low coefficient of frictioncharacteristic and a second surface having a “hand enhanced”characteristic. Fabrics woven from such multilayered fibers are idealfor use in socks, garments, wound treatments, diving apparel and othergarments or devices in which a low coefficient of friction material isundesirable on the inner surface as it would feel uncomfortable on theskin, but is desirable on the, outer surface because it would permitmore movement or gliding action.

[0071] Multilayered fibers could be produced in which the lowcoefficient of friction surface is opposed by a surface which is porousto allow either the migration of medicines into the skin or theabsorption of moisture from the skin. Uniformly low coefficient offriction coated continuous filament or staple would be significantlyless desirable in such applications because the uniformly lowcoefficient of friction filament/staple is more costly.

[0072] The fibers of the present invention, which are made from one ormore low coefficient of friction materials, are more cost effective thanstandard low coefficient of friction filaments and staple. This isbecause only a portion of the invention's fibers contain low coefficientof friction material, while many of the standard low coefficient offriction filaments and staple are completely coated or surrounded withlow coefficient of friction materials. Since low coefficient of frictionmaterial is a premium product and the fibers of the invention containless such material than the standard low coefficient of frictionfilaments and staple, the fibers of the invention are relatively cheaperthan the standard low coefficient of friction filaments and staple.

[0073] Another embodiment of the present invention, as seen in FIG. 10,is a dental pick comprising a relatively high coefficient of frictionportion spaced between two, continuous, relatively low coefficient offriction portions, such that each continuous portion traces a path alongthe length of the pick. It is envisioned that the thickness of thedental pick is from about 5 mil to about 100 mil; preferably, from about8 mil to about 30 mil; most preferably, from about 12 mil to about 20mil. The relatively high coefficient of friction portion is comprised ofpolyester, nylon, acrylics, aramids, polyethylene, polyurethaene andplastic copolymers. Suppliers include, for example, DuPont, Nylestar,Wellman and Foss. One of ordinary skill in the art would understand inlight of the present disclosure that more than one relatively polymericcomponent may be used, such as, for example, a blend of two, three orfour different polymeric components may be used. The relatively lowcoefficient of friction portion is comprised of, but is not limited to,PTFE, boron, HALAR™, molybdenum sulfide, ultrahigh molecular weightsilicone, siloxane, silicone/silane modified polymers, graphite,fluorinated high molecular weight polyolefins or cyclic organiccompounds, non-modified polyolefins, or other fluorinated polymers.Suppliers of the low friction portion include, for example, DuPont, DowComing, Ausimont and General Electric.

[0074] Although preferred embodiments of the present invention andmodifications thereof have been described in detail herein, it is to beunderstood that this invention is not limited to those preciseembodiments and modifications, and that other modifications andvariations may be affected by one skilled in the art without departingfrom the spirit and scope of the invention as defined by the appendedclaims.

What is claimed is:
 1. A fiber comprising a relatively low coefficientof friction portion and a relatively high coefficient of frictionportion, wherein the relatively low coefficient of friction portion isadjacent to the relatively high coefficient of friction portion
 2. Afiber comprising a relatively low coefficient of friction portion and arelatively high coefficient of friction portion, wherein when the fiberis viewed in cross-section, the relatively low coefficient of frictionportion is about 50% of the total cross-section of the fiber, andwherein the relatively low coefficient of friction portion is adjacentto the relatively high coefficient of friction portion.
 3. A dentalfloss comprising a continuous relatively high coefficient of frictionarea spaced between two continuous relatively low coefficient offriction areas.
 4. A dental floss comprising a plurality of filaments,wherein each filament comprises a relatively low coefficient of frictionportion and a relatively high coefficient of friction portion.
 5. Adental floss comprising a plurality of filaments, wherein each filamentcomprises a relatively low coefficient of friction portion and arelatively high coefficient of friction portion, and wherein the totallow coefficient of friction portion of the plurality of filaments isabout 50% of the cross sectional area of the floss.
 6. A dental flosscomprising first and second filaments, wherein the first filament has arelatively high coefficient of friction and the second filament has arelatively low coefficient of friction, wherein the first and secondfilaments are each about 50% of the total volume of the dental floss,and wherein the first and second filaments are substantially evenlydispersed throughout the dental floss.
 7. A dental floss comprising aninner core surrounded by an outer core, wherein the inner core comprisesfilaments having a relatively high coefficient of friction, and whereinthe outer core comprises filaments having a relatively low coefficientof friction.
 8. A method of producing a fiber, comprising the steps of:forming a sheet of material through coextrusion, said coextruded sheethaving at least a first outer layer, a second outer layer, and a centerlayer; wherein said center layer is made up of a material having ahigher coefficient of friction than the material making up at least oneof said outer layers; and orienting and slitting the coextruded sheet toform fibers, such that the top surface of said fibers are made-up of thesame material as said first outer layer, the bottom surface of saidfibers are made up of the same material as said second outer layer, andthe side surfaces of said fibers are made up of the same material assaid center layer.